This invention relates in general to a method of effecting migration, by electrophoresis, of a dispersed phase in a continuous liquid phase, but finds particular, though not exclusive, application to electrophoretic separation of the dispersed phase. One particular application is to electrophoretic separations in non-aqueous solutions.
Such techniques find important practical application for the removal of a dispersed phase from a continuous liquid phase, but, more generally, can be used merely for increasing the concentration of the dispersed phase in one locality of the fluid with corresponding reduction of dispersed phase concentration elsewhere in the continuous liquid phase. The invention, in particular, addresses the problem of electrophoretic separation of dispersed phase or contaminant in or from a continuous liquid phase which is of comparatively high conductivity, e.g. higher than about 10.sup.-8 (.OMEGA..m).sup.-1, but it also covers electrophoretic separation for liquids of lower conductivity, e.g. about 10.sup.-12 (.OMEGA..m).sup.-1, or even insulating liquids. A preferred field of application of the invention is where the continuous liquid phase is a petroleum or hydrocarbon liquid. Such liquids, which include shale and coal liquids, residual oils and polar solvents typically exhibit conductivities in the range 10.sup.-12 to 10.sup.-5 (.OMEGA..m).sup.-1, or more usually 10.sup.-10 to 10.sup.-6 (.OMEGA..m).sup.-1, or 10.sup.-9 to 10.sup.-6 (.OMEGA..m).sup.-1, or 10.sup.-8 to 10.sup.-6 (.OMEGA..m).sup.-1, or even 10.sup.-7 to 10.sup.-6 (.OMEGA..m).sup.-1. The dispersed phase can be a solid, liquid droplets or gas bubbles.